The Russian soldier who has confessed to the deadly shooting spree in Gyumri will go on trial in Armenia, Prosecutor-General Gevorg Kostanian insisted late on Wednesday after angry protests against the Armenian authorities’ failure to have custody of the suspect.

“I can assure you that the criminal will be prosecuted in the territory of the Republic of Armenia and we all will be able to monitor the entire process of justice,” Kostanian told reporters after an emergency meeting with President Serzh Sarkisian.

“You will witness tomorrow robust actions in that direction by Armenia’s law-enforcement bodies, which I think will make it clear to everyone that Armenia will steadfastly administer the entire process of holding accountable any individual who has committed a crime against a citizen of Armenia,” he said.

Kostanian added that he will travel to Gyumri on Thursday morning to repeat these assurances to local residents outraged by Monday’s killing of six members of a local family. But he did not clarify whether the Russian soldier accused of carrying out the massacre, Valery Permyakov, will remain in Russian military custody until his trial.

More than a thousand people rallied in Gyumri earlier in the day to demand that Permyakov be handed over to Armenian law-enforcement authorities. Kostanian’s office, the Armenian police and the Investigative Committee sought to calm them with separate statements saying that the suspect will not avoid prosecution.

In a related development, Russia’s First Deputy Defense Minister Arkady Bakhin met with his Armenian opposite number, Davit Tonoyan, in Yerevan on Thursday to discuss the high-profile murder case that has cast a shadow on close military ties between their countries. According to the Armenian Defense Ministry, Bakhin told Tonoyan that a Russian Defense Ministry commission headed by him has “identified all guilty persons” in an internal inquiry which it has conducted at the Russian military base headquartered in Gyumri.

Permyakov has served there since December. He is said to have deserted his unit shortly before the shootings.

A ministry statement quoted Bakhin as saying that the arrested suspect remains in Armenia. “Further work within the framework of the criminal case will be carried out by relevant bodies of Armenia and Russia,” the statement added without elaborating.

The Armenian Investigative Committee announced earlier in the day that it has levelled multiple murder charges against Permyakov and will conduct a number of forensic tests as part of its inquiry. The law-enforcement agency said it is also trying to establish the Russian soldier’s “path of escape, possible hideouts and circumstances of his capture.”

Permyakov was reportedly caught by Russian border guards while attempting to cross into Turkey on Monday night. They then sent him back to the Russian army base.

The Russian ambassador in Yerevan, Ivan Volynkin, stressed that both Russian and Armenian investigators are trying to solve the crime and “coordinating their efforts” for that purpose. In that regard, he disapproved of a demonstration which Armenian civic activists plan to hold outside his embassy on Thursday.

“I can understand those people and their emotions because there was a savage crime whose perpetrator must he held accountable,” Volynkin told the Russian radio station Sputnik. “People certainly have a right to come here and express their views and emotions. But I think that this issue must not be politicized.”